Changes in blood acetaldehyde levels after ethanol administration in alcoholics

Serial changes in blood ethanol (Et-OH) and acetaldehyde (Ac-CHO) levels following a single oral administration of 0.8 g/kg of Et-OH were determined in order to clarify the metabolism of Ac-CHO in alcoholic liver disease (ALD). The Et-OH metabolic rate (EMR) in alcoholics either with or without liver disease was significantly higher than the rate in nonalcoholics. Peak values of blood Ac-CHO levels and the Ac-CHO/EMR ratios in ALD were significantly higher than those in subjects with nonALD or alcoholics and nonalcoholics without liver disease. In the type I aldehyde dehydrogenase isozyme deficient cases (unusual type), blood Ac-CHO levels and Ac-CHO/EMR ratios were very high and the levels remain at a plateau until 90 minutes after Et-OH administration and then decreased relatively quickly. Changes in blood Ac-CHO levels and Ac-CHO/EMR ratios in ALD were similar to those in cases of the unusual type. These results indicate that Ac-CHO metabolism in ALD is decreased relative to its production and that this decrease might be due to increased production of Ac-CHO in the nonalcohol dehydrogenase pathway located in the microsomes, in which degradation of Ac-CHO was slow.